Ball spline shaft pair with through hole in middle
Technical Field
The invention relates to the technical field of transmission devices, in particular to a ball spline shaft pair with a through hole in the middle.
Background
In the field of the existing transmission device, the ball spline pair has been replaced by a sliding friction pair more and more due to the good rolling friction, small resistance, stable operation and other performances, but the application of the ball spline pair still has great limitation. The conventional ball spline pair structure has insufficient sealing performance and is difficult to adapt to the working requirements of special environments such as field, water and land amphibious and the like; or the internal air pressure is closed and lacks circulation, and extra sliding resistance can be generated along with the change of the air pressure in the axial stretching process, so that the transmission effect is influenced, and the service life is prolonged.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a ball spline shaft pair with a through hole in the middle, so as to realize application in the transmission occasions requiring large displacement compensation or frequent axial expansion and contraction.
In order to achieve the purpose, the power of the ball spline shaft pair is input from the end of the ball spline shaft, the ball spline shaft is inserted into the ball spline sleeve, a plurality of rows of raceways are processed on the ball spline shaft and the ball spline sleeve, a ball retainer is arranged between the ball spline shaft and the ball spline sleeve, the ball retainer is axially provided with a ball hole corresponding to the raceways, balls are embedded in the ball hole and roll along the raceways, so that the torque transmission and the axial telescopic sliding of the ball spline shaft pair are realized, and the other end of the ball spline sleeve is welded with the connecting shaft into a whole to realize the power output of the ball spline shaft pair; the ball spline shaft and the connecting shaft are respectively provided with a through hole which can keep the air pressure balance between the inside of the ball spline shaft pair and connecting parts at two sides, reduce the sliding resistance caused by the change of the air pressure and realize the weight reduction.
And a first shaft retaining ring and a second shaft retaining ring which are used for limiting the ball retainer and ensuring that the balls always work at proper positions are arranged on two sides of a rolling path of the ball spline shaft, the second shaft retaining ring is arranged on the inner side of a shaft shoulder of the ball spline shaft, and the distance between the shaft shoulder and the lip seal is greater than the working tensile length of the ball spline shaft.
And a lip seal for preventing dust, water and grease leakage of the ball spline shaft pair is arranged between the opening part of the ball spline sleeve and the ball spline shaft, and is axially fixed by a hole retaining ring.
Compared with the prior art, the invention adopts the structural design of the ball spline shaft and the connecting shaft with the through hole in the middle, can keep the air pressure balance between the inside of the ball spline shaft pair and the connecting parts at the two sides, and reduces the sliding resistance generated by the change of the air pressure; the lip seal is used at the auxiliary opening part of the ball spline shaft, so that the effects of dust prevention, water prevention and grease leakage prevention can be achieved, the adaptability of the auxiliary ball spline shaft to special environments such as field, water and land amphibious environments is improved, and the service life of the auxiliary ball spline shaft is prolonged. The invention has simple and compact structure and convenient installation and use, and is mainly used for occasions requiring larger displacement compensation or frequent axial extension and retraction in a transmission device.
Drawings
FIG. 1 is a schematic diagram of the present invention.
In the figure: 1. a connecting shaft; 2. a ball spline housing; 3. a first shaft retainer ring; 4. a ball bearing; 5. a ball retainer; 6. a second shaft retainer ring; 7. lip seal; 8. a hole retainer ring; 9. a ball spline shaft; 10. a shaft shoulder; 11. and a through hole.
Detailed Description
As shown in fig. 1, the power of the ball spline shaft pair of the present invention is generally input from the end of the ball spline shaft 9, the ball spline shaft 9 is inserted into the ball spline housing 2, a plurality of rows of corresponding raceways are formed on the ball spline shaft 9 and the ball spline housing 2, a ball retainer 5 is disposed between the ball spline shaft 9 and the ball spline housing 2, the ball retainer 5 is axially provided with a ball hole corresponding to the raceway, balls 4 are embedded in the ball hole and roll along the raceway, so as to realize torque transmission and axial telescopic sliding of the ball spline shaft pair, and the other end of the ball spline housing 2 is welded with the connecting shaft 1 into a whole, so as to realize the power output of the ball spline shaft pair. The ball spline shaft pair structure can reduce the sliding resistance of the middle telescopic shaft (under the same working condition, because the rolling friction is much smaller than the maximum static friction and the sliding friction, under the general condition, the rolling friction is only 1/40 to 1/60 of the sliding friction resistance), reduce the friction heating, and more flexibly and quickly respond to the telescopic requirement of the length change of occasions requiring larger displacement compensation or frequent axial telescopic transmission.
A first shaft retaining ring 3 and a second shaft retaining ring 6 are installed on two sides of a rolling path of the ball spline shaft 9, the ball retainer 5 can be limited, balls 4 are guaranteed to work in proper positions all the time, the second shaft retaining ring 6 is arranged on the inner side of a shaft shoulder 10 of the ball spline shaft 9, the distance between the shaft shoulder 10 and the lip seal 7 is larger than the work stretching length of the ball spline shaft, and therefore interference between the shaft shoulder 10 and the lip seal 7 is avoided when the ball spline shaft 9 works in the stretching process.
Through holes 11 are formed in the ball spline shaft 9 and the connecting shaft 1, so that air pressure balance between the inside of the ball spline shaft pair and connecting parts on two sides can be kept, sliding resistance caused by air pressure change is reduced, and a weight reduction effect can be achieved.
A lip seal 7 is arranged between the opening part of the ball spline housing 2 and the ball spline shaft 9 and is axially fixed by a hole retainer ring 8, and the lip seal 7 can play a role in preventing dust, water and grease leakage of the ball spline shaft pair, so that the service life of the ball spline shaft pair is prolonged, and the maintenance or replacement cost is reduced; meanwhile, water or impurities can be prevented from entering the transmission part of the ball spline shaft pair, the corrosion rate of parts is reduced, the internal lubricating environment is protected, the transmission resistance is reduced, and the working requirement of the ball spline shaft pair in a special environment is met.